X.—THE GEOMETRIDAE. 
SELIDOSHMA LEUCHLABA. 
(Selidosema leucelaea, Meyr., Trans. N.Z. Inst. xli., 6; Selidosema 
productata, Huds., N.Z. Moths, pl. ix., 10, 14.) 
(Plate XVI., fig. 12 @, 13 9; Plate Il., fig. 14 larva.) 
This handsome species has oecurred at Ohakune, Mas- 
terton and Wellington in the North Island, and at Christ- 
church, Otira, Mount Cook, Dunedin and Invercargill in 
the South Island. It is probably fairly common wherever 
miro, or totara trees, are abundant. 
The expansion of the wings is about 13 inches. The fore- 
wings of the male are rich yellowish-brown clouded with blackish 
along the costa, in the disc and on the veins; the first and second 
lines are very indistinct or obsolete; there is a conspicuous 
series of creamy-white blotches on the subterminal area forming 
an irregular broken band; another series of four smaller blotches 
parallel to the dorsum, and a very wavy whitish subterminal line. 
The hind-wings are ochreous tinged with grey, and with faint 
traces of a brownish subterminal line. The pectinations of the 
antennae of the male are much shorter than in either Selidosema 
productata or S. fascialata. In the female the white markings 
on the fore-wings are very much more extensive and irregular, 
and the ground colour much darker which gives the entire wing 
a black and white mottled appearance with a broad white sub- 
terminal band. The hind-wings are greyish-ochreous with a grey 
discal dot, and two wavy grey subterminal lines. 
There is slight variation in both sexes in respect of 
the depth of the ground colour of the fore-wings, and the 
extent of the white markings. 
The egg is oval, slightly smaller at one end, with the surface 
strongly honey-combed; its length is about one-thirty-second of 
an inch, and its colour is pale green, becoming pale pink about 
a week after being laid. 
The young larva, when first hatched, is about 4 inch long, 
very slender, with the head ochreous-brown and the body yellow- 
ish-green; there are two broad reddish-brown lateral lines, which 
become confluent on the last two segments, and a few short 
black bristles. After the second moult the larva is pale brown, 
with obscure darker brown dorsal and sub-dorsal lines. 
The full-grown larva is about 14 inches in length; the head 
is very small, dark brown, with shining black markings; the 
body is rather slender, stouter posteriorly, with a pair of humps 
on the back of segments 6, 9 and 12; its general colour is 
yellowish-brown with numerous fine irregular dark brown wavy 
markings; the skin of the larva is somewhat wrinkled and 
roughened; there is a series of large elongate-oval dull green 
spots on the back of segments 2 to 8 inclusive, and a series of 
similar markings on the sides of segments 5 to 8 inclusive; the 
second segment is almost entirely green, and there are obscure 
greenish patches on the sides of segments 11 and 12; a few 
isolated black bristles are scattered over the larva. Some larvae 
are wholly brown, whilst others have the green markings much 
larger than usual, there being considerable variation in this 
respect. 
This caterpillar is fairly active at night, or when dis- 
turbed. During the daytime, however, it clings firmly to 
a twig with its prolegs, holding its body rigidly extended 
and in this position defies detection. The foodplants are 
miro (Podocarpus ferrugineus) and totara (P. totara), 
and the general colouring and shape of the larva causes it 
141 
to resemble, in the closest’ possible degree, the twigs of 
those trees. It is in fact a most perfect instance of the 
simultaneous development of structure, colour, and instinct 
for protective purposes. 
The perfect insect appears from October till March, 
and frequents forests where miro and totara trees are 
abundant. It is sometimes found at considerable eleva- 
tions. The beautiful mottled colouring of the fore-wings 
is very protective, when the insect is resting on lichen 
covered tree-trunks. 
SELIDOSEMA MONACHA. 
(Selidosema monacha, Huds., Trans. N.Z. Inst. xxxv., 245 pl. 
xxx., 4; Selidosema maculosa, Howes, ib. xlvi., 96.) 
(Plate XVI., fig. 25 4, 26 9.) 
In the North Island this very striking species has 
occurred commonly near Whakapapa, at about 4,000 feet, 
on the lower slopes of Mount Ruapehu. In the South 
Island it has been found at Otira, and on the Lake Harris 
track (3,000 feet), near the head of Lake Wakatipu. 
The expansion of the wings of the male is 12 inches; of the 
female fully 14 inches. The fore-wings are white traversed by 
nunerous broken, jagged transverse lines; in the male these 
lines are more suffused, mixed with yellowish-brown, and the 
discal area is heavily sprinkled with blackish scales; in both 
sexes there is a terminal series of black dots, and the cilia are 
white barred with black. The hind-wings are greyish-ochreous 
in the male, pale grey in the female; there is a darker discal 
dot; a strong slightly waved transverse line below the middle, 
and several paler lines towards the termen. 
Sometimes the black transverse lines are very much 
suffused and in these individuals the black colouring pre- 
dominates. 
The female of Selidosema leucelaea has a superficial 
resemblance to the present insect. I am, however, confi- 
dent that the two species are absolutely distinct. 
The larva, which feeds on Phyllocladus alpinus in 
January, is about 1 inch in length, cylindrical, of almost 
uniform thickness; there is a distinet wart on the back 
of segment 12. General colour, dull green with black mark- 
ings, each mark thickly speckled with greyish-white and 
dull reddish; there are two indistinet sub-dorsal lines on 
segments 2-4; conspicuous sub-dorsal blotches on segments 
5-9; minute black white-centred sub-dorsal spots on seg- 
ments 10 and 11; the whole of the back of segments 12 
and 13 is blackish speckled with grey, the wart dull red. 
No distinct lateral markings. The head is reddish-grey, 
darker behind, with a black stripe down each side. Legs 
reddish-grey barred with black. Prolegs grey speckled 
with black. The larva is well protected when resting on 
the stems of its foodplant. 
The perfect insect appears from November till Feb- 
ruary, and may be looked for on mountains towards the 
upper edge of the forest. 

